* Fix several issues in TrackerMedianFlow implementation
Particularly, add possibility to tune optical flow parameters for a median
flow tracker.
* Improve code of TrackerMedianFlow
Replace a lot of calls of std::vector::erase by one call of
std::remove_if.
* Delete unused code, use norm from OpenCV
* medianFlow:turn getMedian method into function, small code cleanup
* TrackerMedianFlow:fixes in parameters I/O, add test for them
* TrackerMedianFlow:replace double with float in temp buffers
* Fix indentation
* TrackerMedianFlow:add absent parameter case handling in read()
* TrackerMedianFlow:use ROI instead of copy when getting a patch
* TrackerMedianFlow:don't calc image pyramids 2 times
* MedianFlowTracker: use cvIsNan()
* MedianFlow: refactor vector filtration code
* MedianFlow: change if statements layout in filterPointsInVectors
Vladislav Sovrasov